1. Field of the Invention
The invention relates to a process of enhancing egg laying in turkeys using epostane.
2. Information Disclosure Statement
Epostane is the United States Adopted Name (1988 USAN and the USP Dictionary of Drug Names, 1961-1987 Cumulative List) for (4.alpha., 5.alpha., 17.beta.)-4,5-epoxy-3,17-dihydroxy-4,17-dimethylandrost-2-ene-2-carbonitri le having the structural formula ##STR1## (representing the enol form) and having utility as an interceptive (pregnancy disrupting) agent.
Christiansen U.S. Pat. No. 4,160,027 issued Jul. 3, 1979 describes epostane as the product of part (f) of EXAMPLE 1, that is, 4.alpha., 5.beta.-epoxy-17.beta.-hydroxy-4,17-dimethyl-3-oxoandrostane-2.alpha.-carb onitrile having the structural formula ##STR2## which represents the keto form of epostane. The patent shows the interceptive utility of epostane in the rat and the monkey.
Epostane has been studied for effects on fertility in numerous mammalian species and the published results of the studies constitute a bibliography which in March of 1989 numbered 66 references, none of which relates to any avian species.
Three of the references for which the bibliography contains abstracts relate to ovulation. De Paolo (J. Endocrinol., vol. 118(1), pp. 59-68, 1988) and Snyder et al. (Proc. Soc. Exp. Biol. Med., vol 176(3), pp. 238-242, 1984) show inhibition of ovulation in the rat with epostane and Webb (J. Reprod. Fertil., vol 79(1), pp. 231-240, 1987) shows increase in ovulation rate in the ewe with epostane.
The only prior art known to applicant relating to use of epostane in an avian species are as follows: (i) an unpublished report showing dose related decrease of plasma progesterone and estradiol concentrations in the chicken therewith. The report is in the form of a letter dated Aug. 19, 1985 from Peter J. Sharp of The Agricultural and Food Research Council Poultry Research Centre at Midlothian, Scotland, to H. Loison of Sterling Winthrop Group Ltd. in Guildford, England, through whom espostane for the work had been supplied; (ii) a publication entitled STERLING DRUG INC. PRESENTATION TO FINANCIAL COMMUNITY dated Oct. 23, 1986 in a part entitled EPOSTANE at pages 79-80 states at page 80 that "[t]he endocrine effects [of epostane] on egg production in poultry are also being pursued" and that "[t]his latter indication is of particular importance in the broiler industry". The first statement merely sets forth a goal and does not identify a species. The second statement identifies the chicken as a species "of particular importance" and does not mention the turkey. Accordingly the presently described invention is not described or made obvious by the publication. Moreover, as shown below epostane was found not effective in enhancing egg laying in the chicken.
Broodiness in the turkey hen is a physiological condition characterized by aggressive territorial nest protection and increase nesting behavior with cessation of egg production, which together with costs of additional labor and facilities needed to maintain broody hens result in significant economic loss in the turkey industry. The presently described and claimed invention fills a need for a solution to the egg production aspect of the problem in the turkey industry.